Stuart



(No Model.)

4Sheets.Sheet I.

G STUART ELECTRICAL PRIMER;

' No. 372,046, Patented Oct. 25, 1887.

- 4 Sheets-Sheet 2.

(No Model.)

0. STUART. -ELEGTRIGAL PRIMER.

No. 372,046. Pate n'ted oct. 25, 1887.

4 Shets-Sheet a.

" (N'Q Model.)

GLSTUART." ELECTRICAL PRIMER.

Patented Oct 25, 188,7.

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4SheetsSheet 4. STUART. v

ELECTRICAL PRIMER.

No. 372,046. Patent ed Oct. 25,1887;

227 15 JF'WWM. v

UNITED STATES PATENT O Eic E.

GEORGE sTUART, OF ELSWICK WORKS, NEWOASTLE-UPON-TYNE, ENGLAND, ASSIGNOR o G. ARMSTRONG, MITCHELL & 00., (LIMITED,) OF sAME PLACE.

ELECTRICAL PRIMER.

SPECIFICATION forming part of Letters Patent No. 372,046. dated October 25, 1887.

Application filed May 31, 1887.

To all whom it may concern.-

Be it known that I, GEORGE STUART, a subjeet of the Queen of Great Britain, residing at the Elswick Works, Newcastle-upon-Tyne,

England, engineer, have invented certain new andusefulImprovementsinElectricalPrimers, of which the following is a specification.

This invention has for its object improvements in electrical primers.

The primers are mainly intended for use with axial vented guns, more especially rapidfire guns. They are of simple construction and possess the great advantage of being easily renewed by being recharged and fitted with a new platinum wire and cap.

The primer is formed of a cylindrical metallic body, by preference screwed on its exterior to screw into the base of a cartridge-case. At its rear end it is formed with an enlarged head,

and its front end, which isreduced'in diameter, has a screw cut around its exterior for a copper cap to be screwed onto. A main cavity is formed centrally in the body from its front end nearly to its rear end. From the 2 5 rear end of the cavity is a passage of smaller diameter to the rear end of thebody. At the extreme rear end of this passage is also a shallow cavity of larger diameter to receiveadisk of ebonite or other non-conducting ,material. 0 Inside of the main cavity formed in the body are placed disks of asbestus, each having a hole through its center. A metallic spindle is passed centrally into the cavity and through the holes in the asbestus disks, and also made 5 to extend through the small passage at the rear end of the main cavity. The spindle has a collar or flange around it to bear upon the disks of asbestus. More disks of asbestus are then inserted and afterward a metallic ring of gas-check form. The ringand asbestus are then subjected to a greater pressure than that produced in the gun. This forces the asbestus into the small passage at the rear end of the cavity and forms it into a solid insulating block. The ebonite insulator is then placed onto the rear end of the metallic spindle, the metallic spindle passing through it and also through a metallic disk, which is embedded in its rear end, and, finally, the end of the 50 spindle is riveted over. The front end of the Serial No. 239,878. (No model.)

metallic spindle has soldered to it a platinum wire, which is also soldered to a pin which projects from the front end of the body. The wire is then surrounded with gun-eott0n, after which the cavity is filled with gunpowder,

' and when the copper cap charged with gun cotton is screwed onto the front of the body the primer is complete and ready for use. On an electrical contact being made by means of an insulated rod passing through the axial vent of a gun, the electricity passes through the central spindle, through the platinum wire, and back again to the battery through the gun, thereby;heating the wire and firing the gun-cotton and powder; this blows out a cork disk, which closes an opening formed in the end of the cap, and fires the cartridge. The cap may be of thin metal and a fresh one used each time that the primer is recharged, or it may be of stout metal and not require renewal. In place of the platinum wire being soldered to the front end of the central spindle and to a pin projecting from the front end of the body, it may be solderedto two metallic pins carried by a disk of insulating material within the cap, one pin at the center and the other near the periphery of the disk. When the cap is screwed on, the pin at the center comes into contact with the end of the main central spindle,and the outer pin is connected by a spiral wire spring to the copper cap, so that the electrical connections are completed when the cap is screwed home. In place of using a metallic cap to screw onto the end of the body, the end of the cavity in the body may, as in the service primer, be closed by a cylinder of cork or other non-conducting ma terial, which has driven into it two brass pins, one into the rear end to come against the end of the central spindle and the other into its side-t0 make contact with the body. In this case the bridge of platinum wire is soldered" to the heads of the two pins. The exterior of the primer may also be formed to the same pattern as the ordinary service primer.

The drawings hereunto annexed show the modified forms of the fuse above described.

Figure 1 is a longitudinal section of the fuse. Figs. 2, 3, 4., 5, and 6 show separate views of some of -the parts of which it is composed. Fig. 7 is a longitudinal section of a modified form of the fuse, in which the front end of the fuse is closed with a cap of solid metal. Fig. 8 shows an end view and longitudinal section of this cap, and Fig. 9 shows a face and edge view of the disk of cork carried by it. Fig. 10 is a longitudinal section of a modified form of the fuse, in which the means adopted for making electrical connections with the ends of the platinum wire are modified. Fig. 11 shows separately the central stem of this fuse. Fig. 12 shows the ebonite disk and platinum wire and inetal'pins carried by it, and Fig. 13 shows a separate view of the coiled spring. Fig. 14 is a longitudinal section of a modified form of the fuse, in which the front end of the fuse is closedin the way adopted in the ordinary service fuse. Figs. 15, 16, and 17 show end and side views of the cylinder of cork, which in this fuse closes the end of the cavity 0. Fig. 18 is a longitudinal section ofthe same fuse made of the same form or pattern as the ordinary service fuse.

In Figs. 1 to 6, Ais the outer metallic body, formed externally to screw into the base of a cartridge-case, and with its front end of reduced diameter and having a screw-thread cut around it for a metal cap, B, to screw onto. 0 is the central cavity in the body A. D is a passage from the rear end of this cavity to another shallow cavity at the rear end of the body. E is an ebonite disk placed in this latter cavity. F is a metallic spindle passing centrally through the cavity 0 and the passage D, ofsmallerdiametcr, and through the ebonite disk E. G is a metallic disk placed in a recess in the rear face of the ebonite disk E. The spindle F passes through this disk G and is riveted over, as shown. H is the packing of compressed asbestus filling the rear end of the cavity C- and the passage D and surrounding the spindle F, some of the packing being in rear of a collar, F, on the spindle and some in front of it. H is a dished metallic washer placed in front of the asbestus packing. I is 'finegrained gunpowder contained in the front end of the cavity 0. J is a fine wire of platinum soldered at one end to the front of the spindle F and at the other end to a metallic pin, K, which is inserted into a hole in the front end of the body A. L is gun-cotton surrounding the wire J and inclosed in the cap B. M is a disk of cork which closes the hole in the front end of the cap.

In the fuse shown at Figs. 7, 8, and 9 the construction is practically the same and the parts are marked with the same letters of reference. The only difference is that the cap B is made of thick in place of thin metal.

In the fuse shown at Figs. 10, 11, 12, and 13 the construction is the same, except that the platinum wire, instead of being soldered to the end of the spindle F and to the pin K, is soldered to two metallic pins, N, carried by an ebonite disk, 0, the head of one of these pins being in contact with the end of the spindle F and the other being in contact with a coiled tallic pins, N, to which the wire J is soldered.

The head of one of the pins comes in contact with the body A, and the head of the other with the end of the spindle F.

Fig. 18 shows a longitudinal section of the same fuse, but outwardly made of the same form as the ordinary service fuse.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claimis 1. The combination, in an electrical primer, of the body having a main cavity extending from its front nearly to its rear end and a passage of smaller diameter extending rearwardly from the main cavity, an insulated rod passing centrally through the passage and cavity, and having upon it, near the rear end of the main cavity, a collar of larger diameter than the said passage, and a packing of compressed asbestus around the collar, substantially as and for the purpose set forth.

2. In an electrical primer, the combination of the body havinga longitudinal main cavity extending from the front nearly to the rear end and a passage of smaller diameter than the cavity extending rearwardly therefrom, an insulated rod passing through the passage and cavity, and having upon it,'near the rear end of the cavity, a collar of larger diameter than the passage, a packing of compressed asbestus around the collar, a fine platinum wire passing from the front end of the insulated rod to the front end of the body, and explosive material around the wire, substantially as and for the purpose set forth.

3. In an electrical primer, the combination of the body having a longitudinal main cavity extending from the front nearly to the rear and a passage of smaller diameter than the cavity extending rearwardly therefrom, an insulated rod passing through the passage and cavity, and having upon it, near the rear end of the cavity, a collar of larger diameter than the passage, the compressed packing around the collar,a fine platinum wire passing from the front end of the insulated rod to the front end of the body, explosive material around the wire, and a screw-cap screwing onto and closing the front end of the body, and having in its end a central hole closed with a disk of cork or like material, substantially as and for the purpose set forth.

4. In an electrical primer, the combination of the body having a longitudinal main cavity extending from the front nearly to the rear end and a passage of smaller diameter extending to the rear end from the main cavity, an insnlated metallic rod passing through the pasof the body, and a screw-cap screwing onto sage and cavity, and having upon it, near the and closing thefront end of the body, and havrear end of the cavity, a collar of larger diing in its end a central hole closedwith a disk ameter than the passage, the compressed packof cork or like material, substantially as and 5 ing around the collar, a non-conducting disk, for the purpose set forth.

O, carrying two metallic pins, N, to which a G. STUART.

fine platinum wire is coupled, one of which \Vitncsses: pins is held against the front end of the insu- \VM. JOHN GREY, lated metallic rod and the other against a Notary Public.

I0 coiled spring which bears against the front end T. PURVIS. 

